Scab

SCAB"Nonunion workman; also car not equipped with automatic air system. (See nonair)
SCIZZOR-BILL"Uncomplimentary term referring to yard or road brakemen and students in train service ...

Scab
Non union member doing work usually contracted by railroads for railway union labor contracts.
Scale ...

SBU Sense and Brake Unit (see also Caboose) Scab Non union member doing work usually contracted by railroads for railway union labor contracts.

See also: Siding, Passenger train, Signal, Track, Throttle